Never actually owned one, the switch came out of a 'H' Production Bugeye I helped an acquaintance build. It 'boasted' having my first attempts at using my then new pipe/horn design knowledge on its intake, exhaust systems. Worked pretty good too, it blew past the bigger bore 'G' production racers in open practice, so while they couldn't cite any rules I'd bent/broken, they made them illegal for not being within the spirit of the rules, so made him run in a modified class he had no hope of placing well in as punishment, ultimately flipping it trying to keep up.
My first 'Sprite' was a '62 MG Midget British club racer sent over for the local BMC dealer's sales manager to race at Sebring, but he only slalomed it a bit before selling it to a family friend who then turned it over to me shortly after since one had to be 21 back then to sign for such purchases. With various alum. panels and alloy cross flow head, etc. it was a lot lighter (< 1 k lbs IIRC), making it a giant killer in stoplight 'grand prixs' against the various Porsches, muscle cars, etc. of the day. Corvettes just went up in (tire) smoke.........
Of course I paid a steep price for my 'fast' life-style, I remember just about fainting when I got my '64 basic liability car insurance renewal, $597/yr due to various tickets. That's not much less than I pay for full coverage on a Toyota Tundra now.
Anyway, the most fun 'car' I've owned was my first, a hot-rodded 'Chevy' 265^3 V8 powered '55 100/4 A-H. The local 289 Cobras had nothing on me, but those 427s and SOHC Mustangs........ Sheesh! Gees, how I miss those days........
GM
My first 'Sprite' was a '62 MG Midget British club racer sent over for the local BMC dealer's sales manager to race at Sebring, but he only slalomed it a bit before selling it to a family friend who then turned it over to me shortly after since one had to be 21 back then to sign for such purchases. With various alum. panels and alloy cross flow head, etc. it was a lot lighter (< 1 k lbs IIRC), making it a giant killer in stoplight 'grand prixs' against the various Porsches, muscle cars, etc. of the day. Corvettes just went up in (tire) smoke.........
Of course I paid a steep price for my 'fast' life-style, I remember just about fainting when I got my '64 basic liability car insurance renewal, $597/yr due to various tickets. That's not much less than I pay for full coverage on a Toyota Tundra now.
Anyway, the most fun 'car' I've owned was my first, a hot-rodded 'Chevy' 265^3 V8 powered '55 100/4 A-H. The local 289 Cobras had nothing on me, but those 427s and SOHC Mustangs........ Sheesh! Gees, how I miss those days........
GM
Anyway, the most fun 'car' I've owned was my first, a hot-rodded 'Chevy' 265^3 V8 powered '55 100/4 A-H. The local 289 Cobras had nothing on me, but those 427s and SOHC Mustangs........ Sheesh! Gees, how I miss those days........
GM
Don't tell anyone in the 'Healy club... they'll crap themselves in a fit of apoplexy.
I grew up around the smells and sounds of the SCCA Paddock, as my uncle raced a DSR dad crewed, and later raced SS cars. My first exposure was at 13 in 1972, seeing/hearing the " ground pounders " run down the back straight, in the rain, at the old park track in Ponca City, Ok. Watching Mack Yates run his 289 Shelby Cobra throw 20" tall rooster tails, and listening to the then unmuffled sound of the small block V-8 scream at 7K as he went by at 160+, well I was hooked for about 20 yrs.
I spent several very enjoyable weeks at the "Run-Off's" in Braselton in the late '70s, early '80s. Alas The sports monetary requirements outstripped my intrest quotient eventually, and having a family became more of a priority.... But not before racing a DSR myself, and then moving to Pro Rally for a couple of years in the mid '80s.
A 900 Lb. Car, with 175 HP, that accelerates like the smell of a fart in an elevator, and corners like its stuck to the ground will put a Sh*t eatin' grin on your face that's difficult to wipe off.
Most of the kids I went to high school with couldn't even figure out how to start my Sprite, much less drive a manual transmission, but it did attract a large portion of the distaff population of my school ( it's so cute! ( the car )).
Memories.....
Me, again. If I move away from Vd=Sd, why not use vented box calculator, and try do get away with even smaller box. AJ Vented Designer gave me this result ( for Thuras's box):
Vb=79l, Fb=49.9Hz, F3=48.8Hz (13 vents,Dv=2cm,Lv=4.7cm)
I can use 4.7cm thick front baffle and just drill 13 holes...But, is F3 of 48.8Hz good enough,
is it 'a big box without bass'?
Vb=79l, Fb=49.9Hz, F3=48.8Hz (13 vents,Dv=2cm,Lv=4.7cm)
I can use 4.7cm thick front baffle and just drill 13 holes...But, is F3 of 48.8Hz good enough,
is it 'a big box without bass'?
I don't know much about speakers in comparison to other posters but would consider 50Hz half power to be very good in practice. At some point its about usable power. - I've had "big bass" with F3 around 57Hz - it didn't go "low" but could be felt pretty far away even outdoors: http://img470.imageshack.us/img470/2526/myk18frazjpgxy0.jpg
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Hmm, where have I read this suggestion before........?
Anyway, there's a right and wrong way to do this and while my experience doesn't agree with others as to what an acceptable in-room F3 is, what's really important here is driver protection and unless you use some form of EQ to hi-pass the speakers and/or only listen to old vinyl, cassette tapes and/or at very low average SPLs, then a typical vented alignment with a ~50 Hz Fb won't protect the driver against audible distortion at relatively low SPLs and more importantly, accidentally 'letting its smoke out' (burning up and/or bottoming out its VC).
Sealed of course is one way, though even it can burn up a driver on sustained LF notes, but at least you get some warning to 'turn it down' as its tone flattens out due to VC heat rise raising the driver's Qts, ergo the speaker's Qtc.
The vented corollary is basically a vented variant of a sealed cab to get most of the sealed alignment's protection, but with a half octave more gain BW.
Unfortunately, this driver's specs is such that it won't protect the driver any better than your alignment even with its higher F3, so about all I can say about yours is than the vents will probably need significant damping as they calculate a very high vent mach speed on dynamic mid-bass, not to mention theoretically exceeding Xmax by a factor of 3.
GM
PS: I agree with Zen Mod, cobbling together a prototype using cheap materials to experiment with tuning is a good plan when many vents are used, especially when damping is required. You may find that best overall performance will be had by making it a Fonken alignment as this driver really wants a relatively big cab and the only way to keep its 'footprint' small is to make it a very tall MLTL which in turn would put the driver too high up for most folks.
(sad jazz notes in my head). Maybe Paul Janda won"be disappointed if BetsyK ends up eventually horn loaded...BH loaded...shaken , but not stirred ...or OB with Alpha15 ...or...Seing the world Onken made me want to jump in. Being a reader of "l'Audiophile" in the eighties i made a pair of Onken boxes with the recommended wood (Nantex: beech plywood) and a pair of Altecs 416 8-C. They work very well, one of the best bass i've ever heard even if they don't go very low (but i got 32 hz with room gain). A little later Jacques Mahul (Focal -JM Lab) tried to make the mini-onken with a driver he made (10 C01) . He reverse engineered the Onken enclosure (Onken maker never gave the formula) and found out that it was only a bass-reflex with n= 6.4; vents on the side being to make the box stiffer. So people make things looking like Onkens but IMO it's useless. I believe the quality comes from the size ansd stiffness of the box and the unique quality of the Altec driver. If i had to do it again i would simply make a big and heavy bass-reflex with good wood, a big vent and few stuffing inside. Maybe i would try to make a better shape than a simple box an break inside reflections.
Jean
Jean
Hi panomaniac,
you're right about the Nantex, very hard for the tools and very heavy, do you think it's still being made?
I went to you site, very good looking. I see that you also were contaminated by the Hiraga virus like many of us in France. I made a 20w hiraga, excellent sound especially with Onken enclosure but no protection, one day one side blew up and it fried one 416, so i took it away. But i still use a 8 w but not "le monstre " which was the version with batteries, only the little monster which is very good also. I never got the luck to hear the Hiraga system in Paris, i regret it. And you may know it: "la revue du son" is dead -end of an era.
Speaking of mini-onken, a friend has just took back the kit 600 (mini onken + 10 C01, mid and tweeter t120 +plaster egg). The bass driver is perfect but the mids and tweeters are rotten. He phoned Focal and they can repair them - after 26 years it's serious business.
Best regards,
Jean
you're right about the Nantex, very hard for the tools and very heavy, do you think it's still being made?
I went to you site, very good looking. I see that you also were contaminated by the Hiraga virus like many of us in France. I made a 20w hiraga, excellent sound especially with Onken enclosure but no protection, one day one side blew up and it fried one 416, so i took it away. But i still use a 8 w but not "le monstre " which was the version with batteries, only the little monster which is very good also. I never got the luck to hear the Hiraga system in Paris, i regret it. And you may know it: "la revue du son" is dead -end of an era.
Speaking of mini-onken, a friend has just took back the kit 600 (mini onken + 10 C01, mid and tweeter t120 +plaster egg). The bass driver is perfect but the mids and tweeters are rotten. He phoned Focal and they can repair them - after 26 years it's serious business.
Best regards,
Jean
i forgot to ask, what do you think of my opinion that it's useless to try to make Onkens with any driver that one may have? By the way the Onken W has only 2 simple vents with no length. Maybe it woud be more rewarding to think about a really good enclosure. An example here:
http://nicolas.davidenko.perso.sfr.fr/caisse-fred/fred128-eclate.jpg
Best regards,
Jean
http://nicolas.davidenko.perso.sfr.fr/caisse-fred/fred128-eclate.jpg
Best regards,
Jean
I don't know, Jean. It's an old debate. Is there something "special" about the Onken/Ultraflex design? Or is it just a bass reflex with really good bracing?
What I can tell you is that any and every Onken style box I've heard, I liked.
Nantex plywood is no more, helas. It was more like iron than wood. Now if I can, I use bamboo plywood. Also very dense, very stiff and very expensive. And pretty.
The 20W class-A was the first amp I built from parts. Wonderful amp, but I over-volted it and blew a channel. My loss was a JBL driver. On the next build I was more careful!
I was lucky enough to hear the Revue du Son system many times. In fact those Altec A5 went on a few jazz gigs with me.
So who knows? Is there magic to those special side ports? Maybe, maybe not. But they can sound very good. And they look so cool.
What I can tell you is that any and every Onken style box I've heard, I liked.
Nantex plywood is no more, helas. It was more like iron than wood. Now if I can, I use bamboo plywood. Also very dense, very stiff and very expensive. And pretty.
The 20W class-A was the first amp I built from parts. Wonderful amp, but I over-volted it and blew a channel. My loss was a JBL driver. On the next build I was more careful!
I was lucky enough to hear the Revue du Son system many times. In fact those Altec A5 went on a few jazz gigs with me.
So who knows? Is there magic to those special side ports? Maybe, maybe not. But they can sound very good. And they look so cool.
Nesha, what is it? You finished the cab, sound impression??
Kevin, GM, Pano Others
I wish I start my onken build with this Ahuja Sound Solutions driver I consider n 6.3 and Rg 2.25 ohms my amp is home built 300B SE with Zo about 2 ohms.
Calculated values are as follows:
L' vent -26.797
S vent -496
Vb total -396.074 letres
can you guys pls check my calculation? I want to cross to 950pb in 300hz tractrix at 600hz using a simple crossover.
What should be Rg value for my set-up? Big box is ok with me. Thanks.
Kevin, GM, Pano Others
I wish I start my onken build with this Ahuja Sound Solutions driver I consider n 6.3 and Rg 2.25 ohms my amp is home built 300B SE with Zo about 2 ohms.
Calculated values are as follows:
L' vent -26.797
S vent -496
Vb total -396.074 letres
can you guys pls check my calculation? I want to cross to 950pb in 300hz tractrix at 600hz using a simple crossover.
What should be Rg value for my set-up? Big box is ok with me. Thanks.
I don't know how you find this volume, with n=6,3 i find 222 liters, which seems more acceptable for a 12 inch driver. 400 liters ? way too much.
By the way,if you don't have it yet, my advice is to buy another driver, this one doesn't seem to be very appropriate, especially with a Qts of 0.69. By just loking at the picture i would say that it looks like average cheap PA driver - compare it to an Altec , a JBL or a TAD. Build an Onken enclosure and use a 300b with this kind of driver seems to be overkill, sorry to be blunt
Best regards,
Jean
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Sorry guys, my idea of Onken has turn into this:
http://www.diyaudio.com/forums/wild-burro-audio/182745-betsyk-ml-tl-tqwt.html ,
Not finished yet.
http://www.diyaudio.com/forums/wild-burro-audio/182745-betsyk-ml-tl-tqwt.html ,
Not finished yet.
Jean you are right about 222ltr if n is 6.3 and Rg is .1 for 300b se the later is not the right value, or am I missing something.
I accept your advice and would not buy this driver for my project.
Petite Onken box matches calculated value if n is 6.9 and Rg is 6.3.
Kevin pls tell us how you reached to your box dimention with your 416 clone.
Regards
I accept your advice and would not buy this driver for my project.
Petite Onken box matches calculated value if n is 6.9 and Rg is 6.3.
Kevin pls tell us how you reached to your box dimention with your 416 clone.
Regards
Hello minhaj,
building an Onken enclosure with the right wood is not a thing that you can do everyday, i think that it's better to do it like it was intended and has worked perfectly for more than 30 years. This particular Onken box and Altec 416 are the couple that work together which has earned itself that legendary reputation, not any driver in any box with the vents on the sides. Koizumi never gave the formula, it was calculated by Jacques Mahul (Focal/JM Lab), for the french magazine l'Audiophile directed by Jean Hiraga, who concluded that it was a bass reflex with n=6.34 by reverse ingeneering. He even made a special driver (Audiom 14 A) with the same parameters to replace the 416 Altec which was stopped. If you use this value of n with any driver it won't work, i wouldn't do that with a JBL 2231 for example.
IMHO it is pointless to take any driver and calculate this Onken box , except for the looks.
Make simply a bass reflex, make it too big so that you can adapt it to your amp by putting things (books, sand,..) to have the right volume, if you make an Onken you will not be able to modify it. But i wouldn't make an enclosure for a special amp, and 300B doesn't see to be the best choice for this kind of design.
By the way Koizumi made the Onken W, for 2 drivers with only two holes as vents, another one looking like the Voice of theatre, so which one is Onken?
Best regards,
jean
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